Electromagnetic stepping device or the like



Dec. 1, 1964 A. R. CONRAD ETAL 3,159,759

ELECTROMAGNETIC STEPPING DEVICE OR THE LIKE Filed Nov. 25, 1962 A8 Z9 3/ 3O "33%; E v ALBERTR co/vmp ER/C A. ROSENAU INVENTOR ATTORNE United States Patent 3,15%,759 ELECTRQMAGNE'HQ STEPPENG BEVKCE C R THE LIKE Albert R. tlonrad, Anaheim, and Eric A. Rosenau, Orange, Calif assignors to Ford Motor Company,

Dearhorn, Mich, a corporation of Delaware Filed Nov. 23, 1962, Ser. No, 239,560

This invention relates to a counter and more specifically to a magnetically actuated and magnetically detented counter.

Counting devices actuated by magnetic forces are well known as disclosed in the U8. Patent 2,571,085 issued to C. F. Cliiififord on October 9, 1951. The past eiiorts in designing prior counter devices have, however, failed to develop a counter having a simple construction and configuration and which operates swiftly, silently and virtually free of wear. Many of the prior art devices utilize an electric relay or solenoid to actuate a mechanical pawl and ratchet. This type of arrangement is inherently noisy and usually develops wear problems due to the pawl riding on the ratchet Wheel.

The instant invention is quite similar to currently used counters except that it does not incorporate a mechanical ratchet and pawl drive. The counter drive in the instant invention is a fully magnetic ratchet and pawl mechanism. The counter is incrementally stepped by a magnetic pawl located adjacent a detent wheel and is detented by means of a magnet placed near this detent wheel. Both driving and detenting are accomplished magnetically. The drive is, thus silent and virtually free of wear.

The general object of this invention is to provide a magnetically actuated and a magnetically detented counter.

Another object of this invention is to provide a counter having a simple construction and configuration and which operates silently and free of wear.

Other objects and advantages of the invention should become apparent when the detailed written description is read in conjunction with the drawings wherein:

FIGURE 1 is a plan view of the counter and associated magnetic drive; and

FIGURE 2 is a front view of the counter and associated magnetic drive.

The counter, shown in FIGURES 1 and 2, includes the counter or numeral wheels ill that are rotatably mounted upon the shaft ill supported in the frame or housing 12. The counter wheels It may be interconnected by any of the well-known digit transfer mechanisms (not shown). A detent wheel 13 is also rotatably mounted on the shaft 11 by the sleeve 14 which is also fixed to the first nu meral wheel 15. Any movement of the detent wheel 13 is transmitted to the numeral wheel 15. The detent wheel 13 has a plurality of abutments or teeth 15 and is bounded by two surfaces 17 and 18. The number of teeth present on the detent wheel will depend on the number system of the counter. When the detent wheel i3 is utilized in a counter operating in accordance with the decimal number system, it will have ten teeth.

A pawl 20 is mounted to slide in the housing 12 and is located adjacent the surface 13 of the detent wheel 13. The pawl Zll should be placed as close as practically possible to the detent wheel 13 in order to minimize the mag netic losses due to the air gap between the pawl Eli and the teeth 16, thereby enabling the counter to operate ciliciently. The pawl 92% is attached by a securing means to the armature 23 of a solenoid 25. The solenoid 2-5 has a return spring as which is interposed between the armature 23 and the base of the solenoid 25. A coil 29 is also included in the solenoid and may be connected by Zhldiljihil Patented Dec. 1, 196:4

the leads 3d and 31 to any of the well-known switching devices to be periodically energized.

The housing 12 includes a bracket 33 made or a magnetic material and a support member 34 made of a nonmagnetic material which supports a detent 35 made of a permanent magnetic material. This detent 35 is located adjacent the tip of a tooth of teeth 16.

The armature 23, pawl 2t detent wheel 13, shaft l1, bracket 33 and the housing 12 form part of an electromagnetic circuit means and are, therefore, made of a low reluctance material such as that known by the registered trademark Murnetal. The electromagnetic circuit means may also include the solenoid 25 and a periodic or intermittent voltage source (not shown).

In operation the delivery of an electrical pulse to the coil 29 of the solenoid 25 will create a magnetic field. This magnetic field will follow a path comprising armature 23, pawl 20, teeth 16, detent wheel 13, shaft ll, bracket 33, housing 12, and solenoid 25. A force caused by this magnetic field will cause the armature 23 to slide in a downward direction compressing the spring 2 5 as shown by the broken. lines in FlGURE 2. The magnetic flux caused by this magnetic field links the pawl 26 to the detent wheen 13 so that the movement of the pawl 20 in a downward direction with the armature 2-3 is transmitted to the detent wheel 13. This movement of the detent wheel 13 is transmitted by the sleeve is to the first or units order numeral wheel resulting in the advancing of the numeral wheel 15 and a unit increase of the value recorded in the counter. Following the termination of the energization of the coil 25* the magnetic field will collapse and, consequently, there will be no magnetic flux density linking the pawl and the detent wheel 13. The armature 23 is then free to be returned to a normal tie-energized position by the return spring 26. The permanent magnet 35 which is aligned with one of the teeth 16 maintains the detent wheel 13 in the advanced position. It should be understood that the magnetic field and associated flux density created by the solenoid must be of such a magnitude that the holding force of the detent magnet is overcome when a pulse is received by the leads 3% and 31.

The magnetic circuit of the permanent magnet detent 35 will follow a path extending from the upper pole of permanent magnet detent 35 through toothed wheel 16, shaft 11, bracket 33 and back to the lower pole of magnetic detent 35. It should be noted in this regard that the support structure 34 is constructed of a nonmagnetic material. There is a considerable air gap, therefore, between the lower pole of the magnetic detent member 35 and the support bracket 33. This magnetic path has a small enough reluctance to permit the magnetic detent 35 to align one of the teeth of the toothed wheel 16 with it when there is no electrical energy applied to the solenoid 25. As stated above, however, this mag netic force is smaller than the magnetic force applied by the solenoid'25 when it is energized and hence it is overcome when the solenoid 25 is energized and the pawl 20 is actuated.

It will be understood that the invention is not to be limited to the exact construction shown and described and that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined in the appended claims.

We claim:

1. in a counter the combination comprising a detent wheel made of a low reluctance material and having a plurality of teeth, the number of said teeth determined by the number system or" the counter, a pawl made of a low reluctance material located adjacent one surface of said detent wheel, said pawl adapted to move along' a straight line, a detent magnet located adjacent said teeth,

and an electromagnetic circuit means for periodically causing a magnetic field and for completing a magnetic circuit, said electromagnetic circuit including said pawl and said detent wheel as an integral part of said circuit, whereby the periodic energization of said electromagnetic circuit causes said pawl to move said detent wheel.

2. In a counter the combination comprising a housing, a detent wheel made of a low reluctance material and having a plurality of teeth, the number of said teeth determined by the number system of the counter, said detent wheel rotatably mounted in said housing, a pawl made of a low reluctance material located adjacent to one surface of said detent wheel, said pawl mounted to slide along a straight line in said housing when subjected to a magnetic field, a detent magnet located adjacent said teeth, and an electromagnetic circuit means for periodically causing a magnetic field and for completing a magnetic circuit, said electromagnetic circuit means including said pawl and said detent wheel as an integral part of said circuit, whereby the periodic-energizertion of said electromagnetic circuit causes said pawl to move said detent wheel.

3. In a counter the combination comprising a detent wheel made of a low reluctance material and having a plurality of teeth, the number of said teeth determined by the number system of the counter, said detent "wheel having a plurality of surfaces, a shaft made of a low reluctance material, said detent wheel rotatably mounted upon said shaft, a pawl made of a low reluctance material located adjacent to one of said surfaces of said detent wheel, said pawl adapted to move along a straight line in said housing when subjected to a magnetic field, a permanent magnet detent located adjacent the tip of said teeth and an electromagnetic circuit means for periodically causing a magnetic field and for completing a magnetic circuit, said electromagnetic circuit means including said pawl, shaft and detent wheel as an integral part of said circuit, whereby the periodic energization of said electromagnetic circuit causes said pawl to move and to thereby move said detent wheel.

4. in a counter the combination comprising a detent wheel made of a low reluctance material and having a plurality of teeth, the number of said teeth determined by the number system of the counter, said detent wheel having a plurality of surfaces, a shaft made of a low reluctance material, said detent wheel rotatably mounted upon said shaft, a pawl made of a low reluctance material located adjacent to one of said surfaces of said detent wheel, said pawl adapted to move along a straight line in said housing when subjected to a magnetic material, a permanent magnet detent located adjacent the tip of said teeth and an electromagnetic circuit means for periodically causing a magnetic field and for completing a magnetic circuit, said electromagnetic circuit means including said pawl, shaft and detent wheel as an integral part of said circuit and said detent wheel, said electromagnetic circuit means adapted to cause a magnetic flux density between said pawl and said detent wheel of such a magnitude that said pawl and detent wheel may move as a unit, notwithstanding the force of said permanent magnet detent, whereby the periodic cnergization of said electromagnetic circuit causes said pawl to slide and to thereby rotate said detent Wheel one increment.

5. In a counter the combination comprising a housing made of a low reluctance material, an electromagnetic solenoid having a coil and armature mounted in said housing, a shaft made of a low reluctance material and rotatably mounted in said housing, a numeral wheel rotatably mounted on said shaft, a detent wheel made of a low reluctance material rotatably mounted on said shaft and connected to said numeral wheel, a pawl made of a low reluctance material attached to said armature and slidably mounted in said housing, said pawl slidably mounted in said housing adjacent to said detent wheel, and a detent magnet located adjacent said detent wheel, said detent magnet having such a magnetic strength that a higher magnetic flux density occurs between said pawl and said detent Wheel than occurs between said detent magnet and said detent wheel when said coil is energized, whereby delivery of an electric pulse to said coil will cause said pawl to move said detent wheel against the magnetic force of the detent magnet.

6. in a counter the combination comprising a housing made of a low reluctance material, an electromagnetic solenoid having a coil and armature mounted in said housing, a shaft made or" a low reluctance material and rotatably mounted in said housing, a numeral Wheel rotatably mounted on said shaft, a detent wheel made of a low reluctance material rotatably mounted on said shaft and connected to said numeral wheel, said detent wheel having a selected number of teeth dependent on the number system of the counter, a pawl made of a low reluctance material attached to said armature and slidably mounted in said housing, said pawl slidably mounted in said housing adjacent to said teeth of the detent wheel, and a detent magnet located adjacent said detent wheel, said detent magnet having such a magnetic strength that a hi her magnetic flux density occurs between said pawl and said detent wheel than occurs between said detent magnet and said detent wheel when said coil is energized, whereby delivery of an electric pulse to said coil will cause said armature and pawl to advance said detent wheel one unit against the magnetic force of the detent magnet.

7. In a counter the combination comprising a detent wheel made of a low reluctance material and having a plurality of teeth, the number of said teeth determined by the number system of the counter, a movable pawl made of a low reluctance material located adjacent one surface of said detent wheel, a detent magnet located adjacent said teeth, and an electromagnetic circuit means for periodically causing a magnetic field and for com pleting a magnetic circuit, said electromagnetic circuit including said pawl and said detent wheel as an integral part of said circuit, whereby the periodic energization of said electromagnetic circuit causes said pawl to move said detent wheel.

References fitted in the file of this patent UNITED STATES PATENTS 

2. IN A COUNTER THE COMBINATION COMPRISING A HOUSING, A DETENT WHEEL MADE OF A LOW RELUCTANCE MATERIAL AND HAVING A PLURALITY OF TEETH, THE NUMBER OF SAID TEETH DETERMINED BY THE NUMBER SYSTEM OF THE COUNTER, SAID DETENT WHEEL ROTATABLY MOUNTED IN SAID HOUSING, A PAWL MADE OF A LOW RELUCTANCE MATERIAL LOCATED ADJACENT TO ONE SURFACE OF SAID DETENT WHEEL, SAID PAWL MOUNTED TO SLIDE ALONG A STRAIGHT LINE IN SAID HOUSING WHEN SUBJECTED TO A MAGNETIC FIELD, A DETENT MAGNET LOCATED ADJACENT SAID TEETH, AND AN ELECTROMAGNETIC CIRCUIT MEANS FOR PERIODICALLY CAUSING A MAGNETIC FIELD AND FOR COMPLETING A MAGNETIC CIRCUIT, SAID ELECTROMAGNETIC CIRCUIT MEANS INCLUDING SAID PAWL AND SAID DETENT WHEEL AS AN 